Wide area network (WAN) optimization increasingly is being used to improve the performance and efficiency of wide area networks that transport data among sites. Various types of WAN optimization (also known as WAN acceleration) are offered by vendors such as Cisco Systems, Riverbed Technology, Juniper Networks, Citrix Systems, and others. Typically, WAN optimization products include a suite of different types of WAN optimization which can generally be categorized as: traffic or flow management; caching; compression; protocol optimization; and error correction. For example, Cisco's Wide Area Application Services (WAAS) product currently includes TCP flow optimization (TFO) which optimizes TCP parameters such as window sizes, maximum segment size, packet sequence numbering, etc. to ensure efficient flow of packets over the WAN. The WAAS optimization suite also includes compression such as LZ, PLZ, or LZR compression, which compresses data prior to transmission and decompresses the data at the far end. A third type of optimization performed by the WAAS product is data redundancy elimination (DRE), which involves caching data at both endpoints and includes the ability to avoid re-transmission of blocks of data that have already been received at the far end. In addition to these TCP-level optimizations (TFO, LZ, and DRE), the WAAS product incorporates application-specific optimization, including optimizers for a number of specific protocols or applications such as HTTP, certain types of file transfers, video streaming applications, and others.
Service providers and enterprises have historically managed their networks by placing network management devices at key points in the network. These network management devices monitor network performance and communicate information to backend network operations centers for troubleshooting and corrective action. As WAN optimization becomes increasingly ubiquitous, it would be desirable to enhance the capability to monitor the impact of the various types of optimization on network performance, from a high level down to the individual transaction level.